1. Field of the Invention
The present invention relates to an automatic thin-section slides manufacturing system and an automated thin-section slides manufacturing method which automatically manufactures thin-section slides for use in physicochemical experiments and microscopic observations.
2. Background Art
Microtome has been known as a conventional tool for use in general in preparing thin section slide samples for physicochemical experiments and microscopic observations. The thin-section slides are prepared by fixing thin sections about several micrometers (for instance, from 3 μm to 5 μm) in thickness on a substrate such as a glass slide. A generally employed method for preparing a thin section sample using a microtome is described below.
An embedded block is prepared by first subjecting a formalin-fixed biological sample taken out from living bodies, laboratory animals, and the like to paraffin substitution, and then solidifying the periphery thereof with paraffin to prepare a solid block. Then, preliminary cutting is carried out by setting the embedded block in a microtome, i.e., a thin sectioning apparatus especially designed for this purpose. By preliminary cutting, the surface of the embedded block is smoothed, and the biological sample, which is intended to be subjected to the experiment or observation, is brought into a state that is exposed to the surface.
Upon completion of preliminary cutting, main cutting is carried out. In this process step, the cutting blade of the microtome slices the embedded block to provide ultra-thin sections at the predetermined thickness. Thin sections having the intended surface can be obtained in this manner. In such a case, more accurate observation data can be made available by slicing the embedded block as thin as possible in the order of microns, since the thickness of the thin section can be brought near to that of a living cell. Accordingly, it is required to manufacture thin sections as thin as possible. The main cutting step is carried out continuously until thin sections are obtained for the desired number.
Subsequently, thin sections thus obtained are flattened in the flattening process. More specifically, because the thin sections obtained by the main cutting are sliced so thinly, they are apt to be wrinkled or curled (U-shaped). Thus, flattening step is necessary to remove the wrinkles or curls from the thin sections.
In general, flattening is performed by using water and hot water. Firstly, the thin section obtained by main cutting is released in water to set a float. In this manner, large wrinkles or curls of the thin section can be removed while preventing the paraffin, which contains embedded therein the biological sample, from sticking with each other. The thin section is then floated in hot water. The wrinkles which remained unremoved by the water flattening or the deformation which has generated during cutting can be removed from the thin section, because the thin sections are more easily extended in hot water.
After finishing hot flattening, the thin section is mounted on a substrate by scooping it onto a substrate such as a slide glass. If flattening is insufficient at this point, the substrate having the thin section mounted thereon is wholly placed on a hot plate and the like to further apply heat. In this manner, the thin section can be further flattened.
Finally, the substrate having mounted thereon the thin section is dried by placing it inside an oven. By drying, the water adhered to the thin section during flattening evaporates, and the thin section is fixed on the substrate.
As a result, a thin section slide sample can be obtained. The thin section slide samples thus manufactured are mainly used in the biological and medical fields.
Recently, needs for understanding comprehensively and histologically the gene or protein expression are increasing, not only in the diagnostic approach employed heretofore for distinguishing normal/abnormal cells from their shapes, but also in due course of the recent progress in genome science. Accordingly, it is required to efficiently and homogeneously manufacture a larger number of thin section slide samples. However, since most of the process steps described above require highly sophisticated technique and experience, skilled operators had to engage manually in the processes, and hence, much time and labor were consumed on the processes.
Accordingly, in order to overcome such inconveniences even if only a little, there is provided a thin section sample manufacturing apparatus which carries out a part of the processes above (reference can be made to, for instance, Patent Literature 1).
The thin section sample manufacturing apparatus automatically carries out a process step of manufacturing the thin sections by cutting the already set embedded block, a step of transporting the thus manufactured thin section on a carrier tape to transfer it on a slide glass, and a step of performing flattening by transporting the thin section together with the slide glass to the flattening apparatus.
In accordance with the thin section sample manufacturing apparatus, favorable thin section slide samples can be manufactured while reducing the burden of the operator and preventing human-induced errors from occurring.
On the other hand, as an apparatus for manufacturing thin section slide samples by utilizing a microtome, there is also provided an apparatus which relates an embedded block with the thin section slide samples manufactured from the corresponding embedded block.
Although there are several apparatuses of this type, there is known an apparatus, for example, which reads the identification information (an identification information imprinted in advance) of the cassette having mounted thereon the embedded block, and which then allocates the thin section to be mounted by displaying the thus read identification information on the substrate such as the slide glass and the like. (For instance, reference can be made to Patent Literature 2)
Further, there is known another apparatus, which reads the data (which is imprinted in advance) of the cassette on which an embedded block is mounted and the identification information (which is data imprinted in advance) of the substrate such as a slide glass on which the thin section is to be mounted, and queries whether the both data match with each other or not (reference can be made to, for instance, Patent Literature 2).
At any rate, any apparatus above enables relating the embedded block with the corresponding substrate. Thus, an operator conducts the operation step of mounting the thin section sliced by using the microtome on the substrate while appropriately applying the flattening process and the like. As a result, the thin section slide samples can be related to the embedded block.    [Patent Literature 1] Published Japanese patent application 2004-28910    [Patent Literature 2] Published Japanese translation of a PCT patent application 2005-509154    [Patent Literature 3] Published Japanese patent application 2005-91358
However, the apparatuses known heretofore as described above still suffered problems as follows.
First, the thin section sample manufacturing apparatus described in the Patent Literature 1 automatically manufactures thin section slide samples from a single embedded block; however, when thin section slide samples are successively manufactured from plural embedded blocks while efficiently exchanging the blocks, there may be cases in which thus manufactured plural thin section slide samples lose the track from which embedded block they had been manufactured. In particular, when the embedded biological samples are organs which look similar to each other in shapes, difficulties are found in distinguishing them from each other. Accordingly, there had been an inconvenience in relating the embedded block with the thin section slide samples.
Particularly in the embedded blocks, it is required to observe the expression of all the major organs of the animal under consideration, and this requires thinly cutting 20 pieces or more embedded blocks per one animal sample. In practice, because the experimental results are statistically processed, the population size of the embedded blocks is generally increased during the experiments, and may easily reach several hundreds. Accordingly, the number of thin section slide samples also became huge as to make them prone to cause the problems stated above.
As a result, it was found impossible to conduct an accurate quality control, and this affected the reliability of the observation using the thin section slide samples.
On the other hand, the apparatuses disclosed in Patent Literatures 2 and 3 cannot automatically manufacture thin section slide samples, and the operator himself or herself had to flatten the thin sections sliced with the microtome, followed by mounting them on a substrate. Thus, not only the operators suffered large burden, but also the process consumed much time and labor.
Moreover, because the thin section slide samples had to be manufactured manually by the operators, even if the substrate should be related in advance with the embedded block, human-induced errors occurred during the process such as the flattening step of the thin sections and the step of mounting the thin section on a substrate, resulting in cases in which the thin section slide samples were incompletely related to the embedded blocks.